If you doubt that autistic symptoms have grown tremendously, talk to any grade school teacher who has taught since the 1970s. Regardless of the exact rate of increase, at over 2% of all children, this is an enormous epidemic that receives incredibly little attention toward discovering and preventing the causes.

In November of 2015, the CDC announced what they refer to as the most accurate tally of the number of U.S. children who are on the autism spectrum: reporting the current count to be 1 in every 45 children aged 3 and over. This number had been reported as 1 in 5,000 in 1975, and 1 in 500 in 1995. In addition to autism, the autism-related symptom complexes labeled as Asperger’s and pervasive developmental disorder are all referred to collectively as autism spectrum disorders, or ASDs. Changes in diagnostic criteria account for some of the increasing numbers of recognized autism cases but cannot account for the large increases in affected children across the decades.

A growing issue. If you doubt that autistic symptoms have grown tremendously, talk to any grade school teacher who has taught since the 1970s. Regardless of the exact rate of increase, at over 2% of all children, this is an enormous epidemic that receives incredibly little attention toward discovering and preventing the causes. ASDs provide a jackpot for the pharmaceutical industry in terms of treating symptoms but large-scale studies for safer treatments or for curative possibilities are practically non-existent.

Attention deficit disorder (ADD) and attention deficit hyperactivity disorder (ADHD) are related in many ways to ASDs, with many overlaps in symptoms, genes, environmental factors suspected to affect them, and in responses to certain treatments. In both ASDs and ADHD, 4 times as many boys are labeled as girls. Between 3 and 7% of children are diagnosed with ADHD in the United States today. For nearly every environmental factor suggested in an ASD study—from toxin exposures to food reactions to prenatal factors—you can find a corresponding ADHD study with a similar finding.

Add these milder but similar symptom complexes to the number of ASD diagnoses and you have an enormous portion of children whose brains are being altered by poorly delineated influences.

In discussing what possible links there can be to the creation of so many autistic children, there is no intention of blame toward any parents. There are plenty of autistic children whose parents did every little thing wonderfully in terms of what we know and believe today, and there are plenty of factors that are well beyond any parent’s control. In attempt to quell this epidemic of affected children, and in hopes of helping those currently affected, I feel that it’s highly important to delve into all possible environmental factors.

Genetics. Early twin studies had many professionals quite convinced that autism was a completely genetic disorder. More recently, improved sibling studies contradict these findings. Reflecting many newer reports, a 2014 analysis of all children born in Sweden over a 25-year period confirms that—in addition to genetics—environmental factors are reportedly responsible for, on average, 50% of the cause of ASDs.

There are numerous gene variations that are found to be more common among ASD children, but not every child with any such genetics develops autism symptoms. There is enormous variation in the genetic findings among ASD children. Many genes may cause a child to be more susceptible to certain environmental exposures such that, without such exposures, this child would not be affected.

Physiological dysfunctions. Numerous research studies are being published that analyze immune dysfunctions, mitochondrial dysfunctions, inflammation, and oxidative stress in relation to autism. Although the physiology aspects of these studies become quite detailed, in general, these are all simply bodily processes that are caused by genetic irregularities, by environmental exposures, or—most likely—by a combination of the two.

Environmental exposures. Evidence points toward most cases along the autism spectrum as resulting from interactions between various genetic factors and assorted environmental exposures during sensitive periods of neurodevelopment; namely in-utero and during infancy. The term environment refers to any kinds of non-genetic influences. These can include such things as air and water pollutants, hormonal or toxin exposures while in the womb, diet, infections, and gut bacterial disruptors. Today, environmental influences are found to be playing ever-greater roles with maladies such as diabetes, asthma, and cancers, leading to ever-increasing numbers of children affected, against a steady backdrop of genetics. The same is true with ASDs.

Out of nearly 200 published articles examining possible environmental toxin influences on ASDs, 89% found associations. In 2014, two separateextensive reviews of available publications weighed the evidence and concluded that environmental influences with substantial evidential links to autism are plasticizers, certain metals, various solvents, air pollutants, and some pesticides. There is strong evidence of a dose-effect relationship for heavy metal exposures and autistic behavior. All of these are of greatest concern when the mother has accumulated exposures or is exposed during pregnancy, although exposure during infancy and toddlerhood can be critical as well.

Acetaminophen (Tylenol) use in mothers and use along with vaccines in young children, fetal and infant perfume exposure, and other less-known possibilities are also suggested potential factors in individual studies. Other known factors include premature birth, an infection or autoimmune irregularity in a mother during pregnancy, or an infection or irregular immune reaction in a young child. Of note, infections or autoimmune irregularities can refer to vaccine exposures as well as to other kinds of exposures or reactions. Suffice it to say that there is certainly no one cause of ASDs. There is likely a countless number of combinations of conditions that have led to each different autism-related case that has developed among children.

Plasticizers. A recent study confirmed earlier indications that high exposure to the plasticizer BPA can be measured in a portion of autistic children. Babies can be exposed to BPAs through baby bottles, formula from BPA-lined cans, teething rings, and plastic toys, and exposure in the womb is thought to have significant impact. Most mothers are frequently exposed, as BPA can be detected in more than 90% of people. In decades past, BPA was used frequently in plastic bottles and many other commercial products. Today, most plastic bottles do not contain BPA however most cans have BPA in their linings. Mothers can also be exposed through such things as handling of cash register receipts and using recycled toilet paper.

Another plasticizer in need of greater attention is phthalate. Studies have not only found elevated levels of plasticizing phthalates in a portion of autistic children but one study has also recognized a reduced ability in certain autistic children to break down phthalates. Developed in the 1920s, the sources of phthalates are far too numerous to mention and they have permeated throughout our environment. A major source of exposure for humans is dietary, especially through milk fats and meat fats. Breastmilks and formula milks are found to contain similar levels of phthalates however breastmilk can also contain factors that help to detoxify such contaminants. Another dominant source of phthalate exposure linked to ASD development is PVC flooring in the home, especially in the parental bedroom. PVC flooring is most typically seen as imitation hardwood flooring or the vinyl type of flooring generally found in hospitals.

Air pollutants. Fabric softeners, second hand smoke, living near traffic, scented candles, and air fresheners are all implicated to some degree as potential contributors to autism. Volatile organic compounds are also implicated. Some of the worst of these can be inhaled from paint removers, wood stains and varnishes, rust removers, spot removers and other cleaning fluids, adhesives, shoe sprays, wood floor cleaners, and outgassing of building materials.

Maternal infections during pregnancy. A large Danish study suggests that viral infections in mothers during their first trimester may be linked to higher rates of autism in their children. This finding brings up the issue of vaccination. However, the most common viral infections that mothers are subject to are not those for which there are vaccines. According to the vaccine inserts, influenza and other vaccines are not well-studied for safety in pregnant women. Because of these two facts, the most protective move for pregnant women is to avoid large gatherings where respiratory infections may exist and to eat well, rest well, and possibly take immune-boosting supplements to decrease their risks of, and seriousness of their reactions to, any infectious diseases.

In addition to early viral illnesses, the only other notable link to autism development from maternal infections during pregnancy is to mothers’ bacterial skin infections. The most common skin infection today is a staph bacterial infection; chiefly MRSA (methicillin-resistant Staphylococcus aureus). With over 23,000 deaths in the U.S. per year, MRSA is clearly of far greater concern than any viral exposure. There’s an interesting link between this infection and vaccines. It turns out that the pneumococcal vaccination program is wiping out bacteria that were previously competing with staph bacteria and keeping them in check. Along with excessive use of antibiotics, the reduction of pneumococcal bacteria throughout the microbiota of the community is allowing an epidemic of staph bacterial infections.

Methylmercury. High in-utero exposure to methylmercury from mother’s accumulated fish consumption has been linked to lower IQs, even though higher omega-3 fatty acid exposure from fish partially out-weighs the negative effects from this mercury. Salmon is one valuable fish that is high in omega-3 fatty acids and low in mercury. Another recent Canadian study linked prenatal methylmercury exposure to ADHD symptoms in Inuit children. Reports have not linked high prenatal methylmercury exposure (such as from fish) specifically to autism.

Digging deeper. One recent study delves more deeply into the possible impacts of many environmental exposures; an extensive study published in 2014 by environmental scientist Cynthia Nevison. First, this researcher evaluated California and U.S. databases on autism and concluded that 75 to 80% of growing autism reports are due to actual rises in the number of affected children, as opposed to alterations in diagnostic methods. She then plotted curves on graphs demonstrating the relative increases or decreases in various environmental factors suggested as possible autism links, versus the rapidly increasing autism curve, from 1970 to 2005. While correlation is not causation, this effort helps to reduce concern over certain factors and creates suspicion toward others.

Exposure levels to non-vaccine mercury sources, such as from dental amalgams and fish, are relatively flat over the years, and those levels in U.S. women are significantly lower than in some other countries, whereas U.S. autism rates are higher. Children’s blood lead levels dropped precipitously before much rise in autism occurred. Dioxins, PCBs, pesticides, and toxic air pollutants such as automobile emissions are shown to have decreased in the U.S. environment over these decades. That these exposure levels do not coincide with the rate of autism diagnoses does not discount their involvement in some cases of autism. There needs to be some other explanation, however, for the exploding rates of autism.

Glyphosate. One large exception to the apparent declines in pesticide usage is glyphosate, the herbicide in Roundup, which is liberally applied to GMO crops. Nevison’s chart of glyphosate usage versus autism rates reveals a strong parallel. Glyphosate has been shown to disrupt gut bacteria. Unusual gut bacterial irregularities are known to occur among children with ASDs. Glyphosate needs to be studied for potential involvement in the skyrocketing rates of autism.

Vaccines. The greatest concerns for many in regards to vaccines are unrelated to autism, except of course in affected families. The question of autism links to vaccines is, however, an important issue on most everyone’s mind today. Unfortunately, the intensive reviews of environmental factors mentioned above eliminated from their data any studies pertaining to toxin exposures related to medications, such as the kinds of mercury or aluminum in vaccines, or to infectious agents (such as found in vaccines). This is a great disappointment; however, it makes some sense because there are powerful conflicts of interest in vaccine safety research, clouding the validity of studies. These, in turn, lead to conflicts in autism research as well.

As said, environmental studies tend to discuss mercury from other sources but ignore ethylmercury, the kind found in thimerosal from vaccines. Of special value in Nevison’s study are her comparisons of autism rates to rates of thimerosal exposures. Autism and thimerosol usage curves rise quite similarly except that as thimerosol was being phased out of childhood vaccines, beginning in 1999, autism rates continued to rise. Nevison points out that usage of thimerosal-containing flu vaccines in pregnant women were increasing just as thimerosol was being phased out of children’s vaccines. Additionally, as mercury exposure for children was reducing, aluminum, another known neurotoxin, replaced it. The increasing administration of aluminum-containing vaccines correlates well with the continued rise in autism rates.

What we do know about vaccines and autism is that many legal cases have been settled in the U.S. and elsewhere, implicating vaccinations as causing autism-like symptoms in certain children.

Ethylmercury. Ethylmercury, the kind of mercury used in vaccines, has long been reported by the CDC to be safer than the known neurotoxin—methylmercury—that which comes from fish, dentistry, and industrial sources. It’s been known that ethylmercury clears rather quickly from the blood, whereas methylmercury persists.

Thomas Burbacher and other scientists examined earlier research about the accumulation of toxic mercury in brains, where peculiar effects on nerve cells were seen—effects also found in the brains of a portion of autistic children. Their own, 2005, research demonstrated that ethylmercury crosses the blood brain barrier, where it converts to a more toxic (inorganic) form that cannot be excreted, thus accumulating in the brain. Among monkeys injected with equal amounts of either methyl- or ethylmercury, those receiving the ethyl (vaccine) version were found to have twice the levels of persistent inorganic mercury in their brains. One study found lasting brain impairments in fetal rats when their mothers were injected with thimerosal. The potential ramifications of these brain alterations from thimerosal-containing vaccines have not yet been well explored, however, there are many parents who feel strongly that they have seen the effects in their own children.

It is known that brain cell mitochondria can be damaged by ethylmercury. It is also known that some children possess genes which cause their mitochondria to be extra sensitive to mercury. This was the circumstance in the famous case of the medical neurologist and PhD father, Jon Poling, whose credentials—along with those of his critical care nurse and lawyer wife—made the vaccine injury of their daughter too difficult for the courts to dismiss.

Since mercury is still found in annual flu vaccines, the development of a genetic test for such sensitivity could potentially prevent some vaccine injuries in those who choose to vaccinate.

Aluminum. Other studies specifically evaluating links between vaccines and autism focus either on mercury or on the MMR vaccine, with mixed findings. Aluminum adjuvant has taken the place of mercury in vaccines and has long been known, experimentally, to be a neurotoxin. Used to spike the body’s immune response to a vaccine, a great number of papers are written about autoimmune disorders induced by aluminum adjuvant exposure. This growing phenomenon was given a name in 2011: Autoimmune Syndrome Induced by Adjuvants, or ASIA. This phenomenon appears to be well-accepted today among the research community and is assumed to explain much of the neurotoxicity related to aluminum. A great number of studies point out potential mechanisms for autistic results from aluminum adjuvants. A ground-breaking 2015 medical textbook reports on studies that reveal these immune reactions and on studies that pinpoint many gene variations strongly connected with such autoimmune reactions to vaccines.

Nevison’s curves of aluminum exposure versus autism rates strongly reflect each other as aluminum exposure levels continued to rise. Two Canadian researchers who are deeply involved in aluminum adjuvant research, first noticing its links to Gulf War Syndrome, stated in 2011 “In our opinion, the possibility that vaccine benefits may have been overrated and the risk of potential adverse effects underestimated, has not been rigorously evaluated in the medical and scientific community.” Along with many otherresearchers, they continue to call for further attention to this issue. The pharmaceutical industry seems to prefer to keep the vaccine discussion pointed at mercury because the bulk of mercury has now been removed from most vaccines. Experimental evidence against aluminum has existed for decades and is rapidly mounting over recent years. This research is important to watch.

Answers? Further research is desperately needed on the environmental factors that are linked to the development of autism-related effects. Many of the potential factors are being reduced in our environment today but the process is definitely lacking. In the meantime, mothers-to-be do what they can to reduce their known toxin exposures, where possible, along with seeking healthy diets. Spirulina and chlorella are shown in many studies to be excellent detoxifiers that carry heavy metals and other toxins out of the body. These can be used prior to and even during pregnancy and breastfeeding to help mothers reduce any accumulation from present and past exposures. Good antioxidant foods and/or supplements for pregnant and lactating mothers, and for formula-feeding and solid-food consuming children can help to reduce inflammatory reactions in children’s bodies and brains. Autism is but one of many health concerns where all of these same efforts may make a difference.

A large review of studies on gut findings among ASD children showed these children to have over 4 times as many GI complaints. Discussion and treatment options for the gut links to ADHD and ASDs can be found in these articles:Gut Flora in Treatment and Prevention of Autism